Harbor porpoises are among the most commonly bycaught cetaceans in European and North American waters, with gill net entanglement causing thousands of deaths annually.
Harbor porpoise bycatch involves acute drowning deaths at a scale that threatens population sustainability in the most affected regions. A porpoise entangled in a gill net cannot surface to breathe and drowns within minutes - acute suffering followed by death for an animal that was simply swimming through its natural habitat. The technology to substantially reduce this exists: acoustic pingers that alert porpoises to net presence reduce bycatch significantly when used consistently. The welfare and conservation cases are aligned: protecting porpoises from bycatch protects individuals from suffering and protects populations from unsustainable mortality. Regulatory requirements for pinger use with better compliance monitoring would represent meaningful welfare and conservation progress.